The revived activity even included some synaptic function, the transmission of signals between neurons.

Details of the study are published in the latest issue of Nature journal.

Lessons learned from the study could in future help doctors find ways to salvage brain function in stroke patients, or test the effectiveness of treatments designed to aid cellular recovery after injury, say the scientists.

The “BrainEx” system developed at Yale could also provide a powerful research tool.

Any future studies involving human tissue or the possible revival of global electrical activity in “dead” animal brains would have to undergo strict ethical supervision, the team stressed.

However, it was unclear that the technique would work in a recently deceased human brain.

The chemical solution lacked many components found naturally in human blood, such as immune system cells.

In Mary Shelley’s famous gothic novel, Dr Victor Frankenstein instils life into a monster created from dead body parts obtained from grave yards and butchers.

British expert Professor Derek Hill, from University College London, said: “This research raises some fascinating questions. Firstly, was this somehow a chance finding, or can it be reliably replicated?

“Secondly, could brains maintained by BrainEx help scientists discover new treatments for brain diseases like Alzheimer’s and Parkinson’s disease, which are proving really hard to treat?

“And thirdly, what are the ethical implications for the way we treat animals after slaughter, and humans after accidents?

“This ingenious experimental work provides challenges and opportunities both to brain scientists and for science policy makers.”